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on_drop_file event trigger deprecrated on_dropfile
Software Versions
- Python: 3.8.10
- OS: Ubuntu 20.04
- Kivy: 2.1.0
- Kivy installation method: Using pip (20.0.2) in a venv
Describe the bug
As the title says, the Window event on_drop_file trigger the deprecated on_dropfile event.
First, it triggers a Deprected warning while the on_dropfile event is not used in user code.
Second, the arguments passed to the function do not match the documentation, either on_dropfile nor on_drop_file.
Expected behavior
I expected only the on_drop_file event to be trigger and that the callback will be called with exactly 3 arguments: filename, x and y.
Instead, the on_drop_file event is called, then appear the Deprecation warning. Moreover, the callback should takes 4 arguments: window, filename, x and y.
To Reproduce
- Run the following code
- Drop a file on the Kivy window
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.core.window import Window
def on_drop_file(window, filename, x, y):
print(window, filename, x, y)
class DropFile(App):
def build(self):
Window.bind(on_drop_file=on_drop_file)
return BoxLayout()
DropFile().run()
Output:
[INFO ] [Logger ] Record log in /home/me/.kivy/logs/kivy_22-03-29_25.txt
[INFO ] [Kivy ] v2.1.0
[INFO ] [Kivy ] Installed at "/home/me/.venv/lib/python3.8/site-packages/kivy/__init__.py"
[INFO ] [Python ] v3.8.10 (default, Mar 15 2022, 12:22:08)
[GCC 9.4.0]
[INFO ] [Python ] Interpreter at "/home/me/.venv/bin/python3"
[INFO ] [Logger ] Purge log fired. Processing...
[INFO ] [Logger ] Purge finished!
[INFO ] [Factory ] 189 symbols loaded
[INFO ] [Image ] Providers: img_tex, img_dds, img_sdl2, img_pil (img_ffpyplayer ignored)
[INFO ] [Window ] Provider: sdl2
[INFO ] [GL ] Using the "OpenGL" graphics system
[INFO ] [GL ] Backend used <sdl2>
[INFO ] [GL ] OpenGL version <b'4.6 (Compatibility Profile) Mesa 21.2.6'>
[INFO ] [GL ] OpenGL vendor <b'Intel'>
[INFO ] [GL ] OpenGL renderer <b'Mesa Intel(R) UHD Graphics 630 (CML GT2)'>
[INFO ] [GL ] OpenGL parsed version: 4, 6
[INFO ] [GL ] Shading version <b'4.60'>
[INFO ] [GL ] Texture max size <16384>
[INFO ] [GL ] Texture max units <32>
[INFO ] [Window ] auto add sdl2 input provider
[INFO ] [Window ] virtual keyboard not allowed, single mode, not docked
[INFO ] [Base ] Start application main loop
<kivy.core.window.window_sdl2.WindowSDL object at 0x7fd2dbfbd0b0> b'/mytestfile.txt' 230 57
[WARNING] [Deprecated ] Deprecated in 2.1.0, use on_drop_file event instead. Event on_dropfile will be removed in the next two releases.: Call to deprecated function on_dropfile in /home/me/.venv/lib/python3.8/site-packages/kivy/core/window/__init__.py line 2106.Called from /home/me/.venv/lib/python3.8/site-packages/kivy/core/window/__init__.py line 1045 by <lambda>().
[INFO ] [Base ] Leaving application in progress...
It's happening by design https://github.com/kivy/kivy/pull/7786#pullrequestreview-873878786.
Documentation for 2.0.0 states that on_dropfile only has filename as argument and documentation for 2.1.0 states that on_drop_file has (filename, x, y, *args) as arguments.
Currently, the on_drop_file event use four positional arguments, instead of three as stated in the documentation: (window, filename, x, y).
Why is there a deprecation warning ? The above code don't make use of the deprecated on_dropfile event.
Instance of WindowBase is omitted but assumed for events in the documentation and the same goes for all documentation of all classes which inherit from EventDispatcher.
@matham made the decision not to check for observers of on_dropfile event and that's why you will get the deprecation warning. It's in the comments at https://github.com/kivy/kivy/pull/7786#pullrequestreview-873878786 (expand the resolved conversation).
Ok, thank you then. I guess nothing can be done from my side to prevent this deprecation warning.
You would have to change Kivy source code to comment-out https://github.com/kivy/kivy/blob/4fbf9059ce5917ac27685d2b5795e4c447a3f571/kivy/core/window/init.py#L1043-L1046 or https://github.com/kivy/kivy/blob/4fbf9059ce5917ac27685d2b5795e4c447a3f571/kivy/core/window/init.py#L2105-L2107 lines and re-compile the framework.
Ahh I didn't connect that not checking for observers would result in always dispatching the deprecated message.
A better solution would be to add a method has_observers here: https://github.com/kivy/kivy/blob/4fbf9059ce5917ac27685d2b5795e4c447a3f571/kivy/_event.pyx#L658 that more efficiently checks whether there are observers at all rather than getting the list.
